Copy drivers from one Armature to another of the same kind
File append from the menus allows the Blender User to move an armature from one file to the other.





Now the two armatures are in the same file.  
Now you can copy and paste Python Scripts or drivers from one armature to the other.  This can be done manually or from another script.  For small amounts of copies I suggest the task be done manually, otherwise via Script.





Of course you may be able to just copy and paste the text of the driver from while file to the other.  Two Blender files can be open at once.
This proposed answer is intended to be a high level guide to complete your task.  This is not a tutorial.
We have not discussed the particulars of a simple copy of a driver from one object to the other.  The detail required to do so was not given in the original question.